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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.view;
     18 
     19 import com.android.internal.util.GrowingArrayUtils;
     20 
     21 import android.os.Handler;
     22 
     23 import java.util.ArrayList;
     24 
     25 /**
     26  * Class used to enqueue pending work from Views when no Handler is attached.
     27  *
     28  * @hide Exposed for test framework only.
     29  */
     30 public class HandlerActionQueue {
     31     private HandlerAction[] mActions;
     32     private int mCount;
     33 
     34     public void post(Runnable action) {
     35         postDelayed(action, 0);
     36     }
     37 
     38     public void postDelayed(Runnable action, long delayMillis) {
     39         final HandlerAction handlerAction = new HandlerAction(action, delayMillis);
     40 
     41         synchronized (this) {
     42             if (mActions == null) {
     43                 mActions = new HandlerAction[4];
     44             }
     45             mActions = GrowingArrayUtils.append(mActions, mCount, handlerAction);
     46             mCount++;
     47         }
     48     }
     49 
     50     public void removeCallbacks(Runnable action) {
     51         synchronized (this) {
     52             final int count = mCount;
     53             int j = 0;
     54 
     55             final HandlerAction[] actions = mActions;
     56             for (int i = 0; i < count; i++) {
     57                 if (actions[i].matches(action)) {
     58                     // Remove this action by overwriting it within
     59                     // this loop or nulling it out later.
     60                     continue;
     61                 }
     62 
     63                 if (j != i) {
     64                     // At least one previous entry was removed, so
     65                     // this one needs to move to the "new" list.
     66                     actions[j] = actions[i];
     67                 }
     68 
     69                 j++;
     70             }
     71 
     72             // The "new" list only has j entries.
     73             mCount = j;
     74 
     75             // Null out any remaining entries.
     76             for (; j < count; j++) {
     77                 actions[j] = null;
     78             }
     79         }
     80     }
     81 
     82     public void executeActions(Handler handler) {
     83         synchronized (this) {
     84             final HandlerAction[] actions = mActions;
     85             for (int i = 0, count = mCount; i < count; i++) {
     86                 final HandlerAction handlerAction = actions[i];
     87                 handler.postDelayed(handlerAction.action, handlerAction.delay);
     88             }
     89 
     90             mActions = null;
     91             mCount = 0;
     92         }
     93     }
     94 
     95     public int size() {
     96         return mCount;
     97     }
     98 
     99     public Runnable getRunnable(int index) {
    100         if (index >= mCount) {
    101             throw new IndexOutOfBoundsException();
    102         }
    103         return mActions[index].action;
    104     }
    105 
    106     public long getDelay(int index) {
    107         if (index >= mCount) {
    108             throw new IndexOutOfBoundsException();
    109         }
    110         return mActions[index].delay;
    111     }
    112 
    113     private static class HandlerAction {
    114         final Runnable action;
    115         final long delay;
    116 
    117         public HandlerAction(Runnable action, long delay) {
    118             this.action = action;
    119             this.delay = delay;
    120         }
    121 
    122         public boolean matches(Runnable otherAction) {
    123             return otherAction == null && action == null
    124                     || action != null && action.equals(otherAction);
    125         }
    126     }
    127 }
    128